The present disclosure relates to a method and apparatus for regulating a combustion process in a plant, such as a power-generating plant, waste incineration plant, or a plant for making cement. A material is converted by the combustion process while air is being supplied. The state of a system in the plant can be described by state variables (x, y) and regulated at least by way of a control loop. In a known method of the type described above, regulation is carried out utilizing a simply structured control loop. The regulation could be optimized using further sensors, if the transition behavior of the control loop were better known.